Traffic lights code for beginners

Hello dear readers! :slight_smile:

I just wanted to post a code of a traffic light control, which easily is built on a breadboard.
This is my first post to hopefully help others that are beginners like my self. :grin:

Anyway…,
You only need 3 leds (red, green & yellow), 3 resistors ? 330?, some wire & an Arduino.

If you need help on how to build the circuit, just click on the link in the code below.

I can post a screenshot of how I built my circuit if requested. Cheers!

/* 
Trafficlights made basic, by inicko. I made a few changes from; [url]www.makeuseof.com/tag/traffic-light-controller/[/url]   |
<_________________________>----------------------------------------------------------------------------|
-------------------------| 
 the loop now goes:      |        I found my changes made a more reallistic light pattern than
 yellow & red to red     |        the original code. At least this is how the traffic lights are -
 red to red & yellow     |        in Sweden as far as I know.
 red & yellow to green   |      
 green to green & yellow |      Hope you enjoy it!  I've just started with programming, so feel free to change anything
 green & yellow to yellow|      if it's wrong or could be written in a better way etc.
 yellow to red           |      It works the way I intended anyway, so I'm happy ;-)!
 ________________________|
 
 */

// defines the pin outputs as the colored leds for ease //

int red = 13;
int yellow = 12;
int green = 11;

// sets the pins 11-13 as outputs //
void setup(){
  pinMode(red, OUTPUT);
  pinMode(yellow, OUTPUT);
  pinMode(green, OUTPUT);
}

// creates the loop that your Arduino will repeat over & over //
void loop(){
  changeLights();
  delay(3000);
}

// the commands that make the leds light up in a specific order // 

void changeLights(){

  // turn off green, then turn yellow on for 2 seconds
  digitalWrite(green, LOW);
  digitalWrite(yellow, HIGH);
  delay(2000);

  // turn off yellow, then turn red on for 5 seconds
  digitalWrite(yellow, LOW);
  digitalWrite(red, HIGH);
  delay(5000);

  // red & yellow on for 2 seconds (red already on) 
  digitalWrite(yellow, HIGH);
  delay(2000); 

  // green on for 5 seconds, turns off red & yellow
  digitalWrite(yellow, LOW);
  digitalWrite(green, HIGH);
  digitalWrite(red, LOW);
  delay(5000);

  // turn on yellow (green already on)
  digitalWrite(yellow, HIGH); 
  delay(100);
}

Whats next with this code, adding ultrasonic rangefinders to see the traffic situation so you don't drive up to a red light in the middle of the night with no cars around?

I was rather thinking of connecting a nuclear bomb that detonates when someone walks or drives when the lights are red

Seems a tadbit costly. Maybe it just deploys a spikestrip under their tires suddenly. But then again, how would you account for legal right turns on red?

where will i get 4way traffic light controller

Well you could either try coding it by your self with my code for a bit of guidance or simply google 4way traffic light.

You always find answers on google ;-)!

sir? will you please give the schematic diagram of traffic light?

thank you very much Sir.

Godbless :)

Here is my version it’s set up to behave in the British style two sets of lights working in a complimentary manner, your welcome to build on it e.g. four way :-

/*
British trafficlights developed by ConradG based on the program Trafficlights made basic, by inicko. I made a few changes from; www.makeuseof.com/tag/traffic-light-controller/ |

<_________________________>----------------------------------------------------------------------------
the loop now goes:
yellow & red to red
red to red & yellow
red & yellow to green
green to green & yellow
green & yellow to yellow
yellow to red
________________________

*/

// defines the pin outputs as the colored leds for ease //

int red = 13;
int yellow = 12;
int green = 11;
int grn = 10;
int rd = 9;

// sets the pins 11-13 as outputs //
void setup(){
pinMode(red, OUTPUT);
pinMode(yellow, OUTPUT);
pinMode(green, OUTPUT);
pinMode(rd, OUTPUT);
pinMode(grn, OUTPUT);

}

// creates the loop that your Arduino will repeat over & over //
void loop(){
changeLights();
delay(2000);
}

// the commands that make the leds light up in a specific order //

void changeLights(){

// turn off green, then turn yellow on for 2 seconds
digitalWrite(green, HIGH);
digitalWrite(rd, HIGH);
delay(2000);

// turn off green, then turn yellow on for 2 seconds
digitalWrite(green, LOW);
digitalWrite(yellow, HIGH);
delay(2000);

// turn off yellow, then turn red on for 5 seconds
digitalWrite(yellow, LOW);
digitalWrite(rd, LOW);
digitalWrite(red, HIGH);
digitalWrite(grn, HIGH);
delay(4000);

// red & yellow on for 2 seconds (red already on)
digitalWrite(grn, LOW);
digitalWrite(yellow, HIGH);
delay(2000);

// green on for 5 seconds, turns off red & yellow
digitalWrite(red, LOW);
digitalWrite(yellow, LOW);
digitalWrite(green, HIGH);
digitalWrite(rd, HIGH);
delay(2000);

}